Yamaha - Woodruff Key Flywheel & Shaft Alignment 90280-04002-00. Overview. This woodruff key is one of those pieces that quietly keeps everything in sync inside your engine. It holds components in the exact position they need to be so timing stays consistent every time you fire up. I've seen engines act completely off just because this small part was worn or slightly out of place. It's not complicated, but it's absolutely essential if you want things running the way they should.. Key Features. Precise Component Alignment - Keeps flywheel and shaft components correctly positioned for proper timing.. Secure Locking Fit - Prevents slipping between connected parts during operation.. Strong Metal Construction - Built to handle torque and continuous engine use.. Yamaha-Specific Fitment - Designed to match factory tolerances for dependable installation.. Engine & Boat Compatibility. Commonly used across Yamaha outboards in flywheel, crankshaft, and other keyed shaft applications. Essential fo